🛡️ CVE-2026-43012 — kernel

🟡 CVSS 5.5 — Medium ✅ No Known Exploit NVD
5.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

net/mlx5: Fix switchdev mode rollback in case of failure

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Fix switchdev mode rollback in case of failure

If for some internal reason switchdev mode fails, we rollback to legacy

mode, before this patch, rollback will unregister the uplink netdev and

leave it unregistered causing the below kernel bug.

To fix this, we need to avoid netdev unregister by setting the proper

rollback flag 'MLX5_PRIV_FLAGS_SWITCH_LEGACY' to indicate legacy mode.

devlink (431) used greatest stack depth: 11048 bytes left

mlx5_core 0000:00:03.0: E-Switch: Disable: mode(LEGACY), nvfs(0), \

necvfs(0), active vports(0)

mlx5_core 0000:00:03.0: E-Switch: Supported tc chains and prios offload

mlx5_core 0000:00:03.0: Loading uplink representor for vport 65535

mlx5_core 0000:00:03.0: mlx5_cmd_out_err:816:(pid 456): \

QUERY_HCA_CAP(0x100) op_mod(0x0) failed, \

status bad parameter(0x3), syndrome (0x3a3846), err(-22)

mlx5_core 0000:00:03.0 enp0s3np0 (unregistered): Unloading uplink \

representor for vport 65535

------------[ cut here ]------------

kernel BUG at net/core/dev.c:12070!

Oops: invalid opcode: 0000 [#1] SMP NOPTI

CPU: 2 UID: 0 PID: 456 Comm: devlink Not tainted 6.16.0-rc3+ \

#9 PREEMPT(voluntary)

RIP: 0010:unregister_netdevice_many_notify+0x123/0xae0

...

Call Trace:

[ 90.923094] unregister_netdevice_queue+0xad/0xf0

[ 90.923323] unregister_netdev+0x1c/0x40

[ 90.923522] mlx5e_vport_rep_unload+0x61/0xc6

[ 90.923736] esw_offloads_enable+0x8e6/0x920

[ 90.923947] mlx5_eswitch_enable_locked+0x349/0x430

[ 90.924182] ? is_mp_supported+0x57/0xb0

[ 90.924376] mlx5_devlink_eswitch_mode_set+0x167/0x350

[ 90.924628] devlink_nl_eswitch_set_doit+0x6f/0xf0

[ 90.924862] genl_family_rcv_msg_doit+0xe8/0x140

[ 90.925088] genl_rcv_msg+0x18b/0x290

[ 90.925269] ? __pfx_devlink_nl_pre_doit+0x10/0x10

[ 90.925506] ? __pfx_devlink_nl_eswitch_set_doit+0x10/0x10

[ 90.925766] ? __pfx_devlink_nl_post_doit+0x10/0x10

[ 90.926001] ? __pfx_genl_rcv_msg+0x10/0x10

[ 90.926206] netlink_rcv_skb+0x52/0x100

[ 90.926393] genl_rcv+0x28/0x40

[ 90.926557] netlink_unicast+0x27d/0x3d0

[ 90.926749] netlink_sendmsg+0x1f7/0x430

[ 90.926942] __sys_sendto+0x213/0x220

[ 90.927127] ? __sys_recvmsg+0x6a/0xd0

[ 90.927312] __x64_sys_sendto+0x24/0x30

[ 90.927504] do_syscall_64+0x50/0x1c0

[ 90.927687] entry_SYSCALL_64_after_hwframe+0x76/0x7e

[ 90.927929] RIP: 0033:0x7f7d0363e047

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Affected software

CVE-2026-43012 is recorded against 2 packages.

  • kernel (from 6.13.0 up to 6.19.12)
  • linux-kernel

Timeline and source

Published on 1 May 2026 and last revised on 15 July 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

CVE-2026-43012 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Medium
CVSS Score 5.5
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2026-05-01
Updated 2026-08-12
Modified 2026-07-15

Affected Packages

Software From version Fixed in
kernel 6.13.0 6.19.12
linux-kernel — —

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